Vaporizing apparatus and film forming apparatus provided with vaporizing apparatus

ABSTRACT

Because an evaporating apparatus for use in an MOCVD film deposition system has a structure in which a plurality of gas passages brings in a gas from the upper direction, the apparatus has a difficulty to position a jet nozzle, and the apparatus is incapable of accurately controlling the pressure and flow rate of a carrier gas mixed with a raw material solution to be issued into an evaporating unit, and it is thus difficult to highly accurately control the composition of MOCVD films. A plurality of gas passages is arranged on a flat, disk-shaped plate. With this configuration, the accurate positioning of the jet nozzle can be made easier, and the composition of MOCVD films can be controlled highly accurately.

TECHNICAL FIELD

The present invention relates to an evaporating apparatus preferably foruse in a film deposition system such as an MOCVD system.

BACKGROUND ART

Patent Document 1: International Publication No. WO 2004/079806

To advance the development of next-generation DRAMs, a challenge is toreliably provide the capacity of capacitors while the cell area isdecreasing in association with finer design rules. In DRAMs up to16-Mbit ones, mutilevel structures such as a stack type, a trench type,and a fin type are adopted for the cell structures of capacitors.However, in order to fabricate 256-Mbit DRAMs or above with the use ofthese mutilevel structure capacitors, problems are an increase in thenumber of process steps caused by complicated processes and a reductionin yields because of increases in step height. Therefore, in recentyears, such studies are proceeding that thin films using high dielectricconstant materials such as Ta₂O₅, Y₂O₃, and HfO₂ are used for dielectricfilms of capacitors. Moreover, as materials having a dielectric constanthigher than that of these oxide materials and having expectation forapplication to DRAMs, (ba_(x)Sr_(1-x))TiO₃, Pb(Zr_(y)Ti_(1-y))O₃, and(Pb_(a)L_(1-a))(Zr_(b)Ti_(1-b))O₃ are thought as promising ones. Inaddition, Bi-layer ferroelectric materials having a crystal structurevery similar to that of superconducting materials are also hopeful, andin recent years, attention is particularly focused on SrBi₂TaO₉ called aYl material because of its excellent drive at low voltage and fatiguecharacteristics. Generally, the formation of an SrBi₂TaO₉ ferroelectricthin film is conducted according to practical, promising MOCVD (MetalOrganic Chemical Vapor Deposition) methods.

Raw materials for ferroelectric thin films are generally three types oforganometallic complexes, Sr(DPM)₂, Bi(C₆H₅)₃, and Ta(OC₂H₅)₅, and eachof these complexes is dissolved in a THF (tetrahydrofuran) solvent foruse as a liquid solution. In addition, DPM is an abbreviation ofdipivaloylmethane.

Their material properties are shown in Table 1.

TABLE 1 Boiling point (° C.)/pressure (mmHg) melting point (° C.)Sr(DPM)₂ 242/14 78 Bi(C₆H₅)₃ 270 to 280/1 201 Ta(OC₂H₅)₅   146/0.15 22THF 67 −109

A system used for the MOCVD method is configured of a supplying unitthat supplies an SrBi₂TaO₉ thin film raw material and an oxidizing agentto a reaction unit, the reaction unit that causes vapor phase reactionand surface reaction on the SrBi₂TaO₉ thin film raw material for filmdeposition, and a collecting unit that collects products generated inthe reaction unit. Then, the supplying unit is provided with anevaporating apparatus for evaporating a thin film raw material.

As an evaporating apparatus before, a metal filter evaporating apparatusis known in which a raw material solution heated at a predeterminedtemperature is dropped onto a metal filter used for the purpose ofincreasing the contact area between an ambient gas and an SrBi₂TaO₉ferroelectric thin film raw material solution, thereby conductingevaporation. However, in this technique, there is a problem that themetal filter is clogged for several times of evaporation and the filtercannot be used for a long time.

In addition, when the raw material solution is a mixed solution of aplurality of organometallic complexes, a mixed solution of Sr(DPM)₂/THF,Bi(C₆H₅)₃/THF, and Ta(OC₂H₅)₅/THF, for example, and this mixed solutionis evaporated by heating, the solvent having the highest vapor pressure(in this case, THF) is first evaporated and the organometallic complexesare deposited and attached on the heating surface, and on this account,such a problem also arises that a raw material cannot be stably suppliedto the reaction unit.

As a technique for solving these problems, an evaporating apparatusdisclosed in Patent Document 1 is known. This evaporating apparatus isconfigured of a dispersing unit that has a gas passage provided with acooling means, the dispersing unit bringing a pressurized carrier gasand a raw material solution into the gas passage for delivering thecarrier gas containing the raw material solution to an evaporating unit,and the evaporating unit that heats and evaporates the carrier gascontaining the raw material solution delivered from the dispersing unit.

FIG. 8 is a cross section depicting a dispersing unit of an MOCVDevaporating apparatus according to the background technique disclosed inPatent Document 1. An evaporating apparatus 201 according to thebackground technique is an evaporating apparatus that brings in acarrier gas from one ends of gas passages 206 and 207, and delivers acarrier gas containing a raw material solution from an outlet port 208,which is the other end of the gas passages 206 and 207, to anevaporating unit for evaporation. Mass flow controllers (MFCs) 209 and210 are provided on one ends of the gas passages 206 and 207,respectively, and manometers 202 and 203 are provided, which are meansfor detecting pressure inside the gas passages 206 and 207. Pressureinside the gas passage is controlled by the MFC, and pressure inside thegas passage is detected at the same time, whereby clogging in the gaspassage can be suppressed and the timing can be informed in advance thatdumps are needed to clean.

As shown in FIG. 8, the dispersing unit of the evaporating apparatusaccording to the background technique is configured of the gas passages206 and 207 that bring in a carrier gas from the upper direction andsolution passages 211 and 212 that bring in a raw material solution fromthe lateral direction. The raw material solution is issued into thecarrier gas in the midway of the gas passage for atomization, the mistis mixed with the carrier gas, the carrier gas is brought together withone in the other passage in the upper part of the outlet port 208, and aplurality of the carrier gases mixed with different raw materialsolutions is issued into the evaporating unit and heated in theevaporating unit, whereby an MOCVD film is deposited in a depositingunit.

As shown in FIG. 8, the portion in which the raw material solutions inthe gas passages are mixed and gases are issued from the outlet port 208is called a center rod head, in which a rod is provided in the center ofthe pipe for concentrating and issuing gases, and the gas pipe istapered at an angle of about 20 degrees. On this account, it isdifficult to conduct the position adjustment and centering of the gaspassages in the dispersing unit. In addition, the portion at which thesolution passage is mounted on the gas passage has a tapered cylindricalsurface, and individual evaporating apparatuses are different from eachother, and thus it is not easy to conduct accurate control of MOCVD filmdeposition processing.

In addition, as described above, because the boiling point of thesolvent of the raw material solution is lower than the boiling point ofthe organometallic raw material, it is necessary to cool the dispersingunit in order to prevent clogging caused by the deposit of organicmetals. However, in the evaporating apparatus according to thebackground technique, because the gas passages 206 and 207 and thesolution passages 211 and 212 are separate pipes, it is difficult touniformly cool all the pipes. Therefore, there is still a problem thatit is not easy to conduct accurate control of MOCVD film depositionprocessing. Moreover, it is difficult to increase the number of gaspassages, three or four gas passages can be provided at best, and theevaporating apparatus is not ready for the formation of sophisticatedMOCVD films using a wide variety of raw materials. In addition, becausethe evaporating apparatus has the structure in which the gas passagesare arranged in the upper part, such a problem also arises that theheight of the evaporating apparatus becomes higher to increase theapparatus size.

DISCLOSURE OF THE INVENTION

Problems that the Invention is to Solve

It is an object of the present invention to provide an MOCVD evaporatingapparatus that is capable of improving the processing accuracy ofmembers for gas passages in a dispersing section and capable ofuniformly cooling a carrier gas mixed with a raw material solution athigh cooling efficiency.

Means for Solving the Problems

A present invention (1) is an evaporating apparatus for bringing in acarrier gas from one end of a gas passage and delivering a carrier gascontaining a raw material solution from an issuing part arranged at theother end of the gas passage to an evaporating unit for evaporation, theapparatus characterized in that a plurality of the gas passages isradially arranged on a flat plate around the issuing part.

A present invention (2) is the evaporating apparatus according to theinvention (1), characterized in that the shape of the lower portion ofthe issuing part is a conical shape projecting downward, and a passagecarrying the carrier gas containing a raw material solution therethroughand a packing member are alternately arranged on the slope of the cone.

A present invention (3) is the evaporating apparatus according to theinvention (1) or the invention (2), characterized in that a coolingmeans for cooling the gas passage is provided.

A present invention (4) is the evaporating apparatus according to theinvention (3), characterized in that a cooling temperature by thecooling means ranges from 0° C. to 35° C.

A present invention (5) is the evaporating apparatus according to theinvention (1) to the invention (4), characterized in that the gaspassage has a plurality of bends on the flat plate.

A present invention (6) is a film deposition system having theevaporating apparatus according to any one of the invention (1) to theinvention (5).

A present invention (7) is the film deposition system according to theinvention (6), characterized in that the film deposition system is anMOCVD system.

A present invention (8) is an evaporation method of bringing in acarrier gas from one end of a gas passage and delivering a carrier gascontaining a raw material solution from an issuing part connected to theother end of the gas passage to an evaporating unit for evaporation, themethod characterized by including the step of delivering the carrier gascontaining a raw material solution to the evaporating unit through aplurality of the gas passages radially arranged on a flat plate aroundthe issuing part.

A present invention (9) is the evaporation method according to theinvention (8), characterized in that the carrier gas containing a rawmaterial solution is delivered to the evaporating unit through the gaspassages and the issuing part cooled at temperatures ranging from 0° C.to 35° C.

A present invention (10) is a film deposition method characterized inthat evaporation is conducted for film deposition in accordance with theevaporation method according to any one of the invention (8) to theinvention (9).

A present invention (11) is the film deposition method according to theinvention (10), characterized in that the film deposition method is anMOCVD method.

Advantage of the Invention

According to the present invention (1), passages for bringing in a rawmaterial are arranged on the flat plate, whereby advantages are exertedthat the processing and positioning accuracy of the passages forbringing in a raw material is improved, and sealing efficiency isenhanced. In addition, the passages for bringing in a raw material areradially arranged on the flat plate, whereby the number of the gaspassages can be increased freely. Moreover, the passages for bringing ina raw material are arranged on the flat plate, whereby the height of theoverall MOCVD system can be lowered. The system can be installed in aclean room with the limitation of height, and the efficiency of use ofspace is improved.

According to the present invention (2), advantages can be exerted thatthe processing and positioning accuracy of a plurality of the gas outletports is improved, sealing efficiency is enhanced, and the efficiency ofassembly work and maintenance efficiency are raised.

According to the present invention (3), advantages can be exerted thatthe cooling efficiency and cooling uniformity of a raw material areimproved, and the controllability of raw material temperatures isenhanced. A plurality of liquid raw materials is mixed just near acooling section and a jet nozzle, and atomized and issued into theevaporating unit, whereby materials having different evaporationproperties are instantaneously evaporated and supplied to a reactor, andthus the growth of a plurality of the raw materials can be made easier,and the controllability and reproducibility of compositions can beimproved.

According to the present invention (4), a raw material can be preventedfrom being deposited, and a gas jet nozzle can be prevented from beingclogged.

According to the present invention (5), the passage for bringing in araw material is bent freely, whereby a secondary swirl flow is inducedin the passage to cause the flowing state of a gas-liquid two phase flowto be a more turbulent flow for promotion of making finer liquidparticles in the passage. In addition, the cooling efficiency of thefluid is also improved. Moreover, it is also possible that pressure inthe passage is increased, and the occurrence of bubbles in thegas-liquid two phase flow is prevented to further stabilize the flow. Aplurality of liquid materials is issued into individual high-speedcarrier gas passages, and the raw materials are sheared to be fineparticles and changed into a mixed gas just near the nozzle for issuingthe gas into the evaporating unit, whereby mixing and evaporation can beconduced in a single evaporating apparatus.

According to the present invention (6), the stoichiometry, impuritycontents, and composition of a film to be deposited can be controlledhighly accurately. In addition, the system is capable of meeting theproduction of films of more complicated chemical formulas using a largenumber of different raw materials.

According to the present invention (7), the stoichiometry, impuritycontents, and composition of an MOCVD film to be deposited can becontrolled highly accurately. In addition, the system is capable ofmeeting the production of MOCVD films of more complicated chemicalformulas using a large number of different raw materials.

According to the present invention (8), the passages for bringing in araw material are arranged on the flat plate, whereby advantages areexerted that the processing and positioning accuracy of the passages forbringing in a raw material is improved, and sealing efficiency isenhanced. In addition, the passages for bringing in a raw material areradially arranged on the flat plate, whereby the number of the gaspassages can be increased freely. Moreover, the passages for bringing ina raw material are arranged on the flat plate, whereby the height of theoverall MOCVD system can be lowered. The system can be installed in aclean room with the limitation of height, and the efficiency of use ofspace is improved.

According to the present invention (9), advantages can be exerted thatthe cooling efficiency and cooling uniformity of a raw material areimproved, and the controllability of raw material temperatures isenhanced. In addition, a raw material can be prevented from beingdeposited, and clogging in the gas passages and in the gas issuing partcan be prevented.

According to the present invention (10), the stoichiometry of a film tobe deposited can be controlled highly accurately. In addition, themethod is capable of meeting the production of films of more complicatedchemical formulas using a large number of different raw materials. Themethod is capable of meeting demands for deposition of diverse thinfilms, for example, formation of a multilayer film of high dielectricconstant thin film/low dielectric constant thin film/ferroelectric thinfilm, various electrode films, various buffer films, and a multilayerfilm of individual element films.

According to the present invention (11), the stoichiometry, impuritycontents, and composition of an MOCVD film to be deposited can becontrolled highly accurately. In addition, the method is capable ofmeeting the production of MOCVD films of more complicated chemicalformulas using a large number of different raw materials.

BRIEF DESCRIPTION OF THE DRAWINGS

[FIG. 1 ] It is a cross section partially depicting an evaporatingapparatus according to a specific embodiment of the present invention;

[FIG. 2 ] (a) is a cross section partially depicting the evaporatingapparatus according to a specific embodiment of the present invention inthe exploded state, and (b) is a schematic diagram depicting a three-waydiverter valve;

[FIG. 3 ] It is a plan view depicting the evaporating apparatusaccording to a specific embodiment of the present invention;

[FIG. 4 ] It is a cross section depicting the evaporating apparatusaccording to a specific embodiment of the present invention;

[FIG. 5 ] It is a cross section depicting the evaporating apparatusaccording to a specific embodiment of the present invention;

[FIGS. 6 ] (a) and (b) are plan views depicting a circular integratedplate of the evaporating apparatus according to a specific embodiment ofthe present invention;

[FIG. 7 ] It is across section partially depicting an evaporating headof the evaporating apparatus according to a specific embodiment of thepresent invention; and

[FIG. 8 ] It is across section partially depicting an evaporatingapparatus according to the background technique.

Description of Reference Numerals and Signs 1: evaporating apparatus 2:manometer 3: evaporating head 4: evaporating unit 5, 40: integratedplate 6, 41: cooling plate 7, 8, 54, 55: primary carrier gas inlet port9, 10, 56, 57: cooling water inlet port 11, 12: cooling water passage13, 16, 33: raw material solution inlet port 14, 15, 34: solvent andpurge gas inlet port 17, 47: raw material discharge port 18, 20, 49, 50,51: gas-solution mixing channel 19, 58: secondary carrier gas inlet port21: jet nozzle 22: atomizing and issuing part 23: upper evaporating pipe31, 32: three-way diverter valve 35: three-way valve connecting port 36,37, 38: valve 39: gas-liquid mixing plate 42: mixture spray nozzle 43:intermediate plate 44: secondary carrier plate 45: atomizing jet nozzle46: heat insulating spatial layer 48: gas passage 52, 53: positioningpin 61: circular integrated plate 62, 63, 64, 65: three-way divertervalve 66: primary carrier gas inlet port 67: cooling water inlet port68: cooling water outlet port 69: solvent and purge gas inlet port 70:raw material solution inlet port 71: secondary carrier gas inlet port81, 94: evaporating head unit 82, 95: evaporating unit 83: upperevaporating pipe 84: lower evaporating pipe 85, 96: three-way divertervalve 86, 97: primary carrier gas inlet port 87, 98: secondary carriergas inlet port 88, 100: evaporating pipe 89: incorporated heater 90, 99:cooling water passage 91, 92, 93: evaporating apparatus 101, 108:integrated plate 102, 109: gas-solution mixing channel 103, 110: carriergas inlet port 104, 111: raw material solution inlet port 105, 112:issuing part 106a, 106b, 113, cooling water inlet port 115: 107, 114:positioning pin 121: mixture spray nozzle 122: gas-solution mixingchannel 123: cooling plate 124: conical mixing part 125: O-ring seal126: jet nozzle 127: secondary carrier nozzle 128: upper evaporatingpipe 201: evaporating apparatus 202, 203: manometer 204, 205: carriergas 206, 207: gas passage 208: outlet port 209, 210: MFC 211, 212:solution passage 213: raw material solution and cleaning liquid inletport 214: raw material solution valve 215: cleaning liquid valve

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the best mode according to the present invention will bedescribed.

(Specific Embodiment of an Evaporating Apparatus)

FIG. 1 is a cross section partially depicting an evaporating apparatusaccording to a specific embodiment of the present invention. FIG. 2( a)is a cross section partially depicting the evaporating apparatusaccording to a specific embodiment of the present invention in theexploded state. The evaporating apparatus according to this embodimentis configured of an evaporating head 3 that has a gas passage providedwith a cooling means in which a pressurized carrier gas and a rawmaterial solution are brought into a gas passage to deliver the carriergas containing the raw material solution to an evaporating unit, and theevaporating unit 4 that heats the carrier gas containing the rawmaterial solution delivered from the evaporating head 3 for evaporation.The evaporating apparatus shown in FIG. 1 is fabricated by assemblingmembers shown in FIG. 2. FIG. 2( b) is a schematic diagram depicting athree-way valve shown in FIG. 2( a).

The evaporating apparatus according to the present invention is anapparatus characterized in the structure of a dispersing section in thata carrier gas is brought in from one end of the gas passage, a rawmaterial solution is issued into the carrier gas in the midway of thegas passage, the carrier gas shears the raw material solution to changethe raw material solution in mist (fine particle state) for dispersingthe solution in the carrier gas, and the carrier gas containing the rawmaterial solution in fine particles (raw material solution dispersedgas) is delivered from an issuing part arranged at the other end of thegas passage to the evaporating unit for heating and evaporation, and aplurality of the gas passages is radially arranged on a flat platearound the issuing part.

The evaporating head 3 has a gas-solution mixing channel (gas passage)18 formed by laying three-way diverter valves 31 and 32 on an integratedplate 5. FIG. 6( a) is a plan view depicting the integrated plate 5shown in FIG. 1 seen from above. A flat plate (integrated plate) 101shown in FIG. 6( a) is a disk-shaped plate radially having six straightgas passages 102 arranged around an issuing part 105 for a raw materialsolution dispersed gas. In the integrated plate 101, the issuing part105 is processed and formed as holes penetrating through the plate, andthe gas-solution mixing channel 102 is processed and formed as a groovepart on the surface of the integrated plate 101. Therefore, thegas-solution mixing channel can be also processed with high processingaccuracy and positioning accuracy with the use of general processingmethods. After that, as shown in FIG. 1, three-way diverter valves arelaid on the integrated plate 5. For the alignment of the three-waydiverter valve with the integrated plate 5, a positioning pin is inadvance formed at a suited position and a recessed part for fitting isformed at the position corresponding to the positioning pin, whereby theplate is only fit in an assembly process to allow accurate positioning.Although not shown in the drawing, a sealing member is suitably providedbetween the three-way diverter valve and the integrated plate, whereby acarrier gas can be prevented from leaking out from the gas-solutionmixing channel formed by laying the three-way diverter valve on theintegrated plate.

At one end of the gas-solution mixing channel 102, a carrier gas inletport 103 is arranged on the side surface of the flat plate to havesupply of a carrier gas (for example, N₂, Ar, and He), whose flow rateand pressure are controlled, from a carrier gas supplying unit, notshown. A pressure detecting device, not shown, is provided on the gaspassage to monitor carrier gas pressure, whereby the timing can beinformed in advance that maintenance is necessary to prevent the gaspassage from being clogged.

In addition, preferably, the cross sectional area of the gas passageranges from 0.10 to 0.50 mm². Processing is difficult to conduct whenthe area is below 0.10 mm². When the area exceeds 0.50 mm², a necessityarises that a high-pressure carrier gas is used at a large flow rate inorder to flow a carrier gas at high speed. When a carrier gas is used ata large flow rate, a large vacuum pump of large capacity is required inorder to keep a reaction chamber at a reduced pressure (for example, 1.0Torr). Because it is difficult to adopt a vacuum pump having an exhaustcapacity over 10,000 l/min (at a pressure of 1.0 Torr), in order to aimat industrial commercial use, the cross sectional area of the gaspassage preferably ranges from 0.10 to 0.50 mm² for carrying a carriergas at a suited flow rate.

The number of gas passages is not limited to six passages. The number ofgas passages may be below or above six passages. Because the gas passagecan be processed and formed as a groove on the flat plate, the gaspassage can be formed with high processing accuracy and positionaccuracy even though the number of the gas passages is increased. It isalso possible that grooves are formed on a plurality of plates forlaying the plates on each other, and in this case, a large number of gaspassages can be formed.

On a cooling plate 6 adjacent to the integrated plate 5 forming thegas-solution mixing channel 18, a cooling means is provided near thegas-solution mixing channel 18. In the specific embodiment shown in FIG.1, a cooling water passage 11 for carrying cooling water through thepassage is formed in the plate. Because the inside of the gas-solutionmixing channel 18 of the evaporating head 3 is affected by heat causedby a heater of the evaporating unit 4, such a problem arises that when araw material solution dispersed gas is heated in the gas-solution mixingchannel 18, the solvent of the raw material solution and anorganometallic complex are not evaporated at the same time but only thesolvent is evaporated, a raw material is deposited in the gas-solutionmixing channel 18 to clog the passage. Then, a raw material solutiondispersed gas flowing through the gas-solution mixing channel 18 iscooled to prevent the event that only the solvent is evaporated.Particularly, it is important to cool the gas passage on the downstreamside from a raw material discharge port 17. Moreover, because agas-solution mixing channel 20 near a jet nozzle 21 is a portion greatlyaffected by heat caused by the heater in particular, it is necessary tosufficiently cool that portion. Preferably, the cooling temperature isbetween the freezing point and boiling point of the solvent, bothinclusive. For example, preferably, the temperature is betweentemperatures of 0° C. and 35° C., both inclusive. Cooling the gaspassage can prevent the occurrence of a blockage because of carbides inthe gas passage (particularly at the gas outlet port) even in a longtime use. The cooling means is not limited to cooling by cooling water,and cooling can be conducted by using other cooling means such as aPeltier element, for example.

FIG. 4 is a cross section depicting the evaporating apparatus accordingto a specific embodiment of the present invention. In FIG. 4, acrosssection depicting the overall evaporating apparatus is shown, which isformed of an evaporating head 81, and an evaporating pipe 82 in anevaporating unit 82 connected below the evaporating head. Theevaporating pipe 88 is heated by a heater 89. Preferably, a heatingtemperature is at a temperature of 350° C. or above. Because thetemperature of the raw material solution dispersed gas cooled near thegas outlet port of the issuing part is suddenly changed between thedispersing section and the evaporating unit, the gas is evaporated atthe moment at which the gas comes out from the gas outlet port. Theevaporated raw material is moved to the lower evaporating pipe, andbrought into the depositing unit, not shown, and an MOCVD film isdeposited onto a substrate. Liquid raw materials having differentevaporation properties are mixed to select a suited evaporatingtemperature, whereby a plurality of raw materials can be stably suppliedfor evaporation under a single evaporation condition.

The gas passages carrying a carrier gas and a raw material solutionthrough the passages are formed in the flat plate, and the flat plate isplaced horizontally, whereby the height of the apparatus can be madelower. The issuing of a raw material solution into the gas passage maybe conducted by spontaneous dropping because of gravity, or may beconducted by such a scheme that pressure is applied to a raw materialsolution tank to issue a raw material solution into the gas passage.When pressure is applied to the solution for issuing, it is unnecessaryto arrange the raw material solution tank above the gas passage, and thetank can be arranged on the side of the gas passage or below thepassage, which allows the height of the apparatus to be much lower.

In addition, in the specific embodiment shown in FIG. 6( a), the shapeof the flat plate 101 is a disk shape. However, the shape is notnecessarily a disk shape, and plates in given flat shapes can be used,including ellipses, rectangles, and polygons.

In FIG. 2, a jet nozzle 42 is mounted on a cooling plate 41 by fittingthe projecting part of the nozzle into a recessed part formed on theplate. FIG. 7 is a cross section partially depicting the evaporatinghead of the evaporating apparatus according to the specific embodimentof the present invention. Because a mixture spray nozzle 121 is mountedas closely contacted with a cooling plate 123 through an O-ring seal125, a raw material solution dispersed gas passing through agas-solution mixing channel 122 and a conical mixing part 124 will notleak outside. The gas having passed through the gas passage is issuedout from a jet nozzle 126 at the tip end of the mixture spray nozzle 121into the evaporating pipe.

The processing accuracy and relative position accuracy of a plurality ofgas outlet ports are determined by the processing accuracy of themixture spray nozzle 121 and the processing accuracy of the grooveparts, and the gas outlet ports can be formed highly accurately ascompared with those according to the background technique that thepositions of a plurality of tapered pipes are adjusted and mounted.Because the shape and relative position of the jet nozzle can beprocessed highly accurately, the ratio of flow rates of gases containinga plurality of raw materials can be accurately controlled, and highquality MOCVD films can be fabricated as stoichiometry, impuritycontents, and compositions are controlled highly accurately. Inaddition, it is unnecessary to adjust the positions of pipes to be gaspassages in the assembly process. In addition, a member in a conicalshape is used to provide sufficiently high sealing effect with the useof a simple packing seal. Moreover, the evaporating apparatus can berepaired by only changing individual parts such as a flat plate and anevaporating head, and difficult positioning operations are unnecessary.Thus, maintenance costs can be reduced, and maintenance work can be madeeasier.

In this embodiment, the case is described in which the jet nozzle in aconical shape is used. However, the shape of the jet nozzle is notlimited to a conical shape. As long as the shape is the shape projectingdownward including pyramids such as a quadrangular pyramid and ellipticcones, advantages such as easy mounting can be obtained as similar tothe case of using the jet nozzle in a conical shape.

FIG. 3 is a plan view depicting the evaporating apparatus according to aspecific embodiment of the present invention. The evaporating apparatusshown in FIG. 3 is a disk integrated mixing-evaporating apparatus. Aplurality of three-way diverter valves is mounted on a disk-shapedintegrated plate. A plurality of raw materials brought in from aplurality of inlet ports is mixed with each other within the toleranceunder individual evaporation conditions, and collectively atomized andissued from the jet nozzle into the heated evaporating unit forinstantaneous evaporation, whereby the ease of composition control andlong term reproducibility can be maintained and ensured.

(Another Specific Embodiment of an Evaporating Apparatus)

FIG. 6( b) is a plan view depicting an evaporating apparatus accordingto another specific embodiment of the present invention. The evaporatingapparatus according to this embodiment is characterized in that theshape of a gas passage 109 formed on an integrated plate 108 is apassage having a plurality of bends between a raw material solutioninlet port 110 and a jet nozzle 112 that is the outlet port of a rawmaterial solution dispersed gas, that is, a passage in a zigzag shape.The passage shape has a plurality of bends, whereby such an advantage isexerted that the effect of cooling a fluid can be enhanced. In addition,a large secondary swirl flow is induced in the passage to cause theflowing state of a gas-liquid two phase flow to be a more turbulent flowfor promotion of finer liquid particles. At the same time, suchadvantages can be exerted that line pressure is increased, and theoccurrence of bubbles in the liquid transport line is prevented tofurther stabilize the flow.

(System of Parallel Arrangement of Single Raw Material Evaporators)

In recent years, demands for a variety of functional thin films areincreasing more and more. With this trend, the types of raw materialsand methods of film deposition are diversified. Moreover, it is alsodesired to meet liquid materials of unique evaporation conditions, quickresponse on the supply side, use of evaporation gases unsuited formixture before a reactor, processes for laying single films of differentatoms, and the like.

FIG. 5 is a modification of an evaporating apparatus for meeting theseneeds. An evaporating apparatus shown in FIG. 5 has a structure in whichsingle raw material evaporators, each having a raw material introductionsystem, a flat plate provided with gas passages, and an evaporatingpipe, are arranged in parallel with the use of a common flat plate. Theparallel structure is constructed to allow readiness for evaporationgases unsuited for mixture before the reaction unit and for processesfor laying different atoms.

(Applications of an MOCVD System)

An MOCVD system using the evaporating apparatus according to the presentinvention can be used for fabricating insulating films fornext-generation DRAMs as well as used for fabricating insulating filmsfor a large capacity FeRAM (Ferromelectric Ramdom Access Memory) andgate insulating films for micro MOSFETs, for example. In the past, forfabrication of ferroelectric films for FeRAMs, the films are usuallyfabricated according to sputtering methods. However, the composition ofa film cannot be changed to cause a problem of low step coverage. Inaccordance with the MOCVD system according to the present invention,operations can be conducted continuously, the stoichiometry of adeposited film can be accurately controlled, and ferroelectric films ofhigher quality can be produced at mass production level. In addition,also for wiring metal films and barrier metals that are deposited bysputtering methods, these films are replaced by MOCVD films, whereby metal films of excel lent coverage can be formed at high speed.

(Applications to Systems Other than the MOCVD System)

The case is described in which the evaporating apparatus according tothe present invention is used in the film deposition system for MOCVDfilms. However, the evaporating apparatus according to the presentinvention can be used for such film deposition systems that thesesystems are as long as the systems in which a raw material solution isdissolved in a solvent, heated and evaporated for depositing a film. Thesimilar advantages can be obtained as those of the apparatus forfabrication MOCVD films. For example, the evaporating apparatus can beused in an ALD (atomic later deposition apparatus).

INDUSTRIAL APPLICABILITY

According to the present invention, an MOCVD evaporating apparatus canbe provided, which is capable of uniformly cooling a carrier gas mixedwith a raw material solution at high cooling efficiency

The invention claimed is:
 1. An evaporating apparatus including anevaporating head, wherein a dispersion section is located within theevaporating head and an evaporating unit, the dispersing section beingconfigured for bringing in a carrier gas from one end of a gas passageand delivering a carrier gas containing a raw material solution from anissuing part arranged at the other end of the gas passage to anevaporating unit for evaporation, the apparatus comprising: a flat plateon which a plurality of the gas passages are radially arranged aroundthe issuing part; and means for cooling at least one of the plurality ofgas passages, wherein each of the gas passages is formed as a groovepart on a surface of the flat plate and is covered by one or severaladjacent members to form a closed passage, and the raw material solutionis issued into the carrier gas in a midway of the gas passages on theflat plate, and the carrier gas shears the raw material solution tochange the raw material solution to mist for dispersing the raw materialsolution in the carrier gas.
 2. The evaporating apparatus according toclaim 1, wherein a shape of a lower portion of the issuing part is aconical shape projecting downward, and the means for cooling is acooling plate with which a mixture spray nozzle is mounted closelycontacted through an O-ring seal.
 3. The evaporating apparatus accordingto claim 2, wherein the gas passage has a plurality of bends on the flatplate.
 4. A film deposition system having the evaporating apparatusaccording to claim
 2. 5. The evaporating apparatus according to claim 1,wherein a cooling temperature of the means for cooling ranges from 0° C.to 35° C.
 6. The evaporating apparatus according to claim 5, wherein thegas passage has a plurality of bends on the flat plate.
 7. A filmdeposition system having the evaporating apparatus according to claim 5.8. The evaporating apparatus according to claim 1, wherein the gaspassage has a plurality of bends on the flat plate.
 9. A film depositionsystem having the evaporating apparatus according to claim
 8. 10. A filmdeposition system having the evaporating apparatus according to claim 1.11. The film deposition system according to claim 10, wherein the filmdeposition system is an MOCVD system.
 12. The evaporating apparatusaccording to claim 1, wherein the cooling device is a cooling plate. 13.An evaporating apparatus including an evaporating head and anevaporating, wherein a dispersion section is located within theevaporating head unit, the dispersing section comprising: a plurality ofgas passages, each gas passage being configured for bringing in acarrier gas from one end of the gas passage and delivering a carrier gascontaining a raw material solution from an issuing part arranged at theother end of the gas passage to the evaporating unit for evaporation; aflat plate on which the plurality of the gas passages are radiallyarranged around the issuing part; and a cooling device configured forcooling at least one of the plurality of gas passages, wherein each ofthe gas passages is formed as a groove part on a surface of the flatplate and is covered by one or several adjacent members to form a closedpassage, and the raw material solution is issued into the carrier gas ina midway of the gas passages on the flat plate, and the carrier gasshears the raw material solution to change the raw material solution tomist for dispersing the raw material solution in the carrier gas.